The present invention relates to a radio paging system and, more particularly to a radio paging system in which a called pager holder is not only alerted but is also supplied with an audible or other message, such as a telephone number, which he is expected to call back.
One example of conventional systems adapted to transmit such "an" additional message is the so-called "Answering Service System". In this system, the telephone exchange office, to which the calling subscriber is connected is adapted to store his message which is to be conveyed to the person who is carrying a paging receiver, while transmitting the paging signal through a radio frequency channel. Upon recognition of his page, as signalled by an alert tone or vibration, the paged party dials a predetermined answering code or telephone number, at a telephone set, to get an access to the stored message.
Another example of a conventional system is known in Japan as a "Super-Bell System", in which the calling party's phone number is stored at the telephone office, in place of the message that is stored in the Answering Service System. When alerted by the paging tone, the paged party dials a predetermined number plus the called party's pager-identification number. In response, the telephone exchange office utilizes the stored number to establish a connection between the paged party and the calling party. This system permits a calling party to place a paging signal through any telephone set which may be located anywhere. This is in clear contrast to the conventional paging system, in which the paged party's calling back is achieved only through the calling party's designated number.
The Answering Service System has a disadvantage in that a third party knowing the predetermined page answering number can get an access to the caller's message stored at the telephone exchange office. Furthermore, the system must assign separate numbers for the pager identification and for the message readout, thus complicating the system as a whole.
Similar problems are involved also in the Super-Bell System, such as the establishment of an undesired connection between a calling party and the third party, who knows the predetermined number. Furthermore, such illicit third party's call makes the desired telephone contact impossible, because the stored calling party's number is erased from the storage once it is read out.